Vibrator



Feb. 14, 1961 v. LOVERDE VIBRATOR Filed Dec. 2, 195'? United StatesPatent 2,912,070 VIBRATOR llwrence V. Loverde, Chicago, Ill., assignorto Oak Manufacturing Co., a corporation of Delaware Filed Dec. 2, 1957,Ser. No. 700,129

3 Claims. (Cl. 310-25) This invention relates to a vibrator andparticularly a vibrator of the type having a reed carrying movablecqntacts for cooperation with stationary contacts. Vibrators of theabove type have an armature disposed at the end of a spring reed, thearmature being adapted to travel back and forth across a magnetic poleface. The vibrator has suitable windings to be actuated by directcurrent interrupted by contacts controlled by the vibrator to maintainthe vibrator continuously in opera tion. Vibrators of this type are usedto interrupt direct di'rrents and generate alternating currents whichmay be stepped up to suitable potential for use in equipment such as,for example, automobile radio receivers.

. In the. operation of a vibrator, it is desirable to maintain. thefrequency of the vibrator substantially constant in. spite of variationsof applied potential to the vibrator Winding. As a rule, an increase inpotential applied to the winding for energizing the vibrator results inincreased amplitude of armature travel and consequently results in achange in frequency. Such an increase in frequency is. undesirable wherecertain loads are present. As examples, a vibrator may providealternating current for the motor of a phonograph or magnetic recorderand reproducer. It is desirable, therefore, to maintain the frequency ofreed vibration in a vibrator substantially constant in spite ofvariations of energization of the vibrator winding due to variations inapplied potential to such windings.

'As isv well known,. a vibrator has at least one winding for creating amagnetic field associated with a ferromagnetic circuit. Theferro-magnetic circuit necessarily an'air gap between the armaturecarried by the reed and the pole face past which the armature isnormally adapted to travel. As a rule, the armature is carried on asteel reed and the frame of the vibrator usually has sufficient iron sothat one air gap between the reed and pole face and possibly another airgap or two between the reed and the frame exists.

In accordance with this invention, means are provided for creating amagnetic shunt to the magnetic path between the pole face and vibratablearmature, said magnetic shunt having a reluctance which is inverselyproportional to the strength of the magnetic field created by thevibrator winding. By proper design of the magnetic shunt, compensationfor variations in peak field strength due to the energizing winding maybe made as a result of variations in peak value of current passingthrough the vibrator winding. In accordance with the invention, thereluctance of the magnetic shunt is automatically adjusted by theintensity of magnetization due to winding energization so that a newvibrator having an improved magnetic shunt will function to maintain asubstantially constant armature amplitude and frequency over widevariations of applied potential to the vibrator winding.

In general, the invention contemplates the provision of a resilientterm-magnetic member for cooperating with the pole piece for the purposeof diverting part of the magnetic flux which ordinarily serves toactuate the 2,972,070 Patented Feb. 14, 1961 armature of the vibrator.While the invention may be applied to different types of vibrators, itwill be disclosed in connection with a common type of vibratorconstruction, it being understood, however, that such vibrator isexemplary.

Referring, therefore, to the drawings Fig. 1 is an elevation partlybroken away of a new vibrator encased in a can, the new vibratorembodying the present invention.

Fig. 2 is a sectional elevation on broken line 2-2 of Fig. 1.

Fig. 3 is a sectional view on line 3-3 of Fig. 1.

Fig. 4 is a sectional view on line 4-4 of Fig. 1.

Fig. 5 is a perspective view of one form of magnetic shunt removed fromthe vibrator.

Figure 6 shows a circuit diagram illustrating the connections of thevibrator.

While the invention may be applied to any type of vibrator, forconvenience the invention is shown as applied to a vibrator which ismore fully disclosed and claimed in United States Patent 2,252,882,issued August 19, 1941. The vibrator comprises base 10 of suitableinsulating material carrying a number of prongs 11 for cooperation witha suitable socket when the vibrator is to be plugged into a circuit.Vibrator 14 has ferro-magnetic frame 16 between the ends of which isclamped reed 17. As a rule, the ends of frame 16 may be spaced andprovided with suitable insulators to create a stack for supporting fixedcontacts 20 on opposite sides of reed 17. Reed 17 itself may carrymovable contacts disposed on opposite sides thereof, the movablecontacts being supported on suitable arms riveted or otherwise securedto the reed. The movable contacts cooperate with the stationarycontacts, closure of the contacts being alternately elfected on one sideor the other side of the reed in accordance with reed vibration.

Fixed contacts '20 and the movable contacts cooperating therewithgenerally are in a circuit including a transformer primary. Reed 17 mayhave a suitable driving contact thereon or movable therewith forcooperation with stationary driving contact 25 secured upon one side offrame 16. The cooperating driving contacts control energization ofvibrator winding 27 disposed at bight 28 of the frame. Within winding 27is ferro-magnetic member 30 extending axially of winding 27 toward thereed. Reed 17 carries armature 32 at the end thereof, the armature beingof soft iron. Armature 32 cooperates with pole piece 33 offerro-magnetic member 30. As shown, the pole piece is offset laterallywith respect to armature 32 in the normal rest position of the reed. Itis understood, of course, that the reed contacts are closed in this restposition.

As illustrated in Figure 6 (this is based upon Figure 8 of the UnitedStates patent previously referred to) winding 27 is connected throughthe driving contacts, including stationary contact 25, to one terminalof a source of direct current such as, for example, battery 60. Theother terminal of battery 60 is connected back to the remaining terminalof winding 27. It will be noted that the remaining terminal of battery60 is also connected to the center tap of primary 61 of transformer 62.The end terminals of primary 61 are connected to the stationary contactsof the vibrator. If the vibrator is provided with rectifying contacts,such as disclosed in the issued patent previously referred to, then thesecondary of transformer 62 may be connected to other stationaryvibrator contacts as more fully disclosed in said patent.

The structure so far described is conventional and upon energization ofwinding 27, the vibrator driving contacts, including stationary drivingcontact 25 will cause armature 32 to vibrate back and forth past polepiece 33. The frequency of reed operation will be detera Y minedby thestiffness of the reed andthe length thereofto a large degree.Except-afor excessive amplitude or armature movement, the frequency ofvibration will remain 'gene'rally constant over-variations of amplitude?In order to control the frequency, and in accordance with the invention,there is provided at least one and preferably two'm'agnetic shunts toby-pass some magnetic flux from reed armature 32.' One shunt consists offerromagnetic angle piece 37 having spring portion 38 andpole pieceportion 40. Spring portion 38 has attaching end 41 and merges into angleportion 42. It-is desirable to increase \the flexibility of springportion 38 and accordingly thisportion may have its width decreased. v

Attaching portion 41 of each shunt is rigidly supported at part 45 of aT-shaped bracket 46 of soft iron. Bracket 46 has attaching part 47 whichmay be bolted to vibrator frame 16 near winding 27. Vibrator frame 16has slots 50 through which pole portion 40 of the-shunt extends. The endof the pole portion of the shunt is disposed in proximity to pole piece33 of the vibrator. The shunt is shaped to clear the end of reed 17. Therest position the. magnetic circuit for saidelectromagnet, at lea'st' one" of each shunt may be preset by bending the shunt or by suitablewashers between the attaching parts of the shunt and bracket. The shuntand bracket are attached to each other at parts 41 and 45 by aniron boltpassing through oneand threaded into the other. Other attachments may-be-used.

The-bobbin upon which winding 27 is wound is of non-magnetic material sothat the magnetic shunt may complete a path from the vibrator frame tovibrator pole piece33. It will be evident that a magnetic shunt pathwill be provided from vibrator pole piece 33-alo'ng shuntpole portions40 and thence to some part or'parts of the Vibrator frame. i As a ruleduring operation, shunts 38 will vibrate-with the'reed, the amplitude ofvibration of portions however being dependent upon the peak value of themagnet-ic field generated by winding 27. The greater the peak-'value'ofthe field due to'winding27, the closer will pole portions 40 approachpole piece 33 of the vibrator and themore magnetic lines of force willbe By proper design of the'magnetic Various means for securing amagnetic shunt to the frame may be provided. The only requirement isthat i to be opened and closed during reed vibration-at which time saidarmature sweeps back and forth past said pole face, connections betweensaid contacts and the winding of said electromagnet so that saidvibrator may maintain itself in operation, said frame and reed formingpart of magnetic shunt comprising an angle'piece of ferro rn'a'g neticmaterial, said angle piece having a spring 'po'rtionf and a poleportion, means for rigidly attaching-said spring portion of said anglepiece to said frame in 'such'ia position that said pole portion extendstoward said'pole' face but stops short thereof to provide anair'gapthere between, said frame and shunt providing a ferro-rnag neticpath from the pole face through part of the frame and said magneticshuntto the pole portion of said shunt adjacent the pole face, said springportion beingizsufli ciently flexible to permit said shunt toadjustitself t6 control the size of the air gap between the pole portionwhereby the reed frequency may be maintained sub stantially constantover variations in existing potential;

2. The' vibrator according to claim-'1 wherein said magnetic shunt issecured to the frame on the outside of the frame'andwherein the poleportion T extends throughaslot in the frame. I I r y I I 3. Theconstruction according to claim 1 wherein two shunt members areprovided, said shunt members being disposed on opposite sides of thepole face along the line of travel of the armature. I a 1 2,547,026 aWinkler Apr. 3; 19 5 1 p, FOREIGN PATENTS: 480,279 Canada Jan. 15,1952

